SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '625f39fc77b5c94b3949600b88c3b846125a2d3e254cf3e239b5dcbdb8b06242' 
  AND token = 'DIaXzwYZuQzr4yfExgcz1yh1RJv+dDvXcmNHSwb0jJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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