SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23ff0ab322592d9b4a38dd5b2b18927a3108369f684928015decef27239f6d75' 
  AND token = 'TA6htZpj6xXXTDtm2OKMEnoSM7l5P+CTlclrtAxgpXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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