SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e54a152c6ce66c76c8822e9b7143666620d750e5d84eaebfc2268153ce0c1c6' 
  AND token = '5hOoAqahfqsjEHxeJ1JpL1JvtrzgmAgSzvRE2rsxgnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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