SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0be254c39f2f81207ed3f31e53b944365fa6b64719653829713fb40221a5085' 
  AND token = 'RKsveeqDkCowEQ48utK7fW5BpQGQ46qR1TDJAWH/V7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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