SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af87eb4fe99136beb887a80e8bd5628c8c36ceee9e3b8d4000f8f05526c7c0bd' 
  AND token = 'C7bAnu4BWl6w1gMr/Jm4OJh9UwSUao3M7kPXo9pmDTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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