SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c271ebff54a1dfe2399380ab2336cf2e3ec5e3521b05ff653dd5e2fd6b5da809' 
  AND token = 'zGty88HQb9H3Ffg0YQbuvVVsvrxoQNquHqYdThq+OkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}