SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '682124b301fbd926c13e3c110fc5655d3ff6dc234e46847e8a58405b375475d3' 
  AND token = 'ik2HncP/2xLPur0cganLDepYFpRCIQSUo7glcZ0mrcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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