SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d90669a136deec9ee11f9f9bef82015eb27f0f8b2da0f5c8ac2af1df3b0793f' 
  AND token = 'rJqjKm6hhLv2G350ogpwxTVenQGTPemhF/dbB9OB6TE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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