SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '941cc843333cc99b34ebe48694998621805b7eb3718720fd7439576fe471828c' 
  AND token = 'L7VI98RtpiZ1bocdogKh5NtZUwxXsy2Lgc3z2UfduaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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