SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '094872bc5c7f0fef305ecc200e45e7ccf9f284922818e959bdc32c24fe49752a' 
  AND token = 'gFfjLugiBOeQEvchXcvNWR7/CHarEI+fdKLF3r8CigQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}