SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad296910f7c82bf52cadfe674b0f4a2d5867f911113a81f1921f2cf26cff89c9' 
  AND token = 'YkMKeasHofCoETsDEsbev97YVP816LXmwnqVuHB+12M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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