SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1868896184005b02abed25d1217b70dd738994bec157468e1be63debad217b93' 
  AND token = 'ek1/HsX3k7cEyM13mpKUL4uNyQrbP5QxBEbfsrxohXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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