SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e16e3dafb2d8bdc84841d3d96ba27cda680d676976d327e92f65b9e9218bd5cb' 
  AND token = '6Uegu2PEKh3jr7+tIxdx7FY57W4J+QR6V5YersmiG6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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