SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95655c83c2c8c8ef00376f5132fadc2d621395103aa218ab894746dd2473a34c' 
  AND token = '+nCcc/8K5lBIfKXVmzdPuIAnXg4fL5hINB5PzWg4IvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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