SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90777d8f3b8e3344ac298ca264fc931bffb9b1a533dbdfac94261e49dcebe070' 
  AND token = 'T/VfrVUL8TT/zKJs2KoPjAGtWJTg3PkhhkhmfxTwQeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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