SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c574e7cd730d002321a22a334147c8864ad173fa7678331bb77fdfafc70aa820' 
  AND token = 'EyWXLiye1Gt+YGACPZ8TB6LaJWwc8TfxWEgvUhKiGCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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