SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6759449ea937b4dacc8614373479fcb3cafb874ed8173bb266f5399bbe522a0d' 
  AND token = 'xl8HTQIKls5fD6Pup+pyAYE/JW+hZ+9LnMLtRgF5BnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}