SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c4ce56dbbdedad6922d2b680326ade4181c2c99fc9b00ec281a083f3f0b7a91' 
  AND token = 'UHjzTfwpateZwYk3LXQWf5NgR5ZiC27Zd17GZIdYXn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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