SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef9db507781b7cfaf1bf918f84e688e17fb313b76d0bceb461f070433fa3da40' 
  AND token = 'wLJKy14ALr90J1FXXEE9hcl+2oL18ZKvvclc8lySdDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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