SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82dc3ee09ceb92fe47d1a1beab4fd728db99101b17bc7e749765a22ee84f3904' 
  AND token = 'zTfOcYGH/wqpbrkVJGhZSzXgV1oV8mN3C9pLozZlc2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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