SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c421757de2f5fae8aacb85b4fa97ee25ef90d2c0244b1ef3cae535b206e292ad' 
  AND token = 'riNUvs5vgY6yamWIFCp++H0Etq/0+BFElCogbBNFFpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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