SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fae87d08e75e118a7839b39eeda466efbb474cae2e832b3814da71d638d4c52' 
  AND token = 'K5WFzxQuNHmpBFoXUfjnBGnCrxGODUDNqOIyGgDEq9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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