SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '259fa2cf2f78857eddc823b99704f6c705ff2b10d13bf6a8f0744aa361a6270c' 
  AND token = '2Jfb+919XwjHH33Ak/qgK6/pu8bMsvZ+tUpUBLi6EL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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