SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b104ab6107522593af6fcb09e4c1e3eab150777e22db60317deaf46ad82f1ab' 
  AND token = '/BcB2/0g9eHdJt6gyFY6RDChNBNSW2w25HhRWJFRnqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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