SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cce3d80d4eab4063c7db8e04f1abb9dd69d7ae58f8371c430126c246458c9ce8' 
  AND token = 'U1APjfVUKSi6ggcsAmBPQTrBkjB3nsL/nJoFjXeEcgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}