SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a74f712a1da405e2cbc4a9994847120965371972b802d4fb9e83aef5a2bc54' 
  AND token = 'iLgAbi3mIAK6ve9/92rTbi0FB6v48wMoUgEggO6U+jk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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