SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb156a0b0c188c7c3cf0c7dc0951ce62abb69222b8a1469f169586e63dd164a2' 
  AND token = 'zhHgYjw5eYCw4hA9dMKGsZE7Z7cRj8mR+sN8SpXG7Jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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