SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d77d59834d74a919e4e9eff06ca353638dd7727d9fd6125bed414374a106f62' 
  AND token = '5/L6brTIcWJzkIGfENonrh/gCew1dv0a2kq13NV1C3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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