SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c97384587d22fc19404012ddb284a92166eceeaf616419ec3ce78e720be397d' 
  AND token = 'L/9iY2J023VVJmYWkfwsvOcvF/RpLOPh68cUuZ4k7LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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