SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddffc0f4df82db94cd753f180feabcbc962eedd1f11eaaef5a4da2b3ce496bad' 
  AND token = 'B1MprUbmUIweHTzC4BAv9dA15fO12tq+zh5kNoyTM2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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