SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03de66dc51d1dd94fcf618177c322b846889339d68e895162426397c2e28236c' 
  AND token = 'dy/8HRkbVai+GrB3Ycb6Mu34R9t0JCnbJXrnTQIXb0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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