SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff550c3f651707f1ce39465ed808252db4959be78eb378d04da6490e5db3577d' 
  AND token = 'otDyBJAzOKsxczi3Po0/newrpa+tTspchnYdUNkwXEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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