SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9970b7f85461dfd5ccff55bad27083dcd78edefec498df08dd864d49a7a3bae4' 
  AND token = '3cR0qOrdBVt5lD9fHUt8W7bfagxpUSZr23qLK+epNRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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