SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c08998982db1535a8a9724da3497b133f235e01d86b2baeb9ac3c1f627f8e01a' 
  AND token = 'JU8CpiaMHYvSdS+zuu/Wx8kI+yjVYd/9urVxj4l8eRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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