SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f88a06c9340eac0bc297dbfb1f93c6dee3bb017e34ec81a493425085fe62d348' 
  AND token = 's0q2BcAImMxgA+gNaFegh4FNYSGf0nHEVAKCFHSNaKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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