SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4789d59ebca72dd41b61e26cb0e7554f9e8ac71ee628aa6055040e6e8caa8c53' 
  AND token = 'ysY4gKgJUnubEE1WP/PkjvPHjSP/wLcrEZopTPF5J9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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