SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e42cb4a023f3af17c05b8b6fefa594855b17aff24a6459d67fd8541bead4b82' 
  AND token = 'rldJorEQIMGNRzarRmv6qfcB8MUSscU9g2ql3FJkvVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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