SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1741bf13fe22923f374f264347f97c6d06b7401ecbcfe5bdbb9b2e487fe0122f' 
  AND token = 'UlUQ8Fc08QphhtRgDuuVOF+HFgVZv6XpFvVjlvH5HiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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