SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f55844be9d160ff82bedf1c72e2150e55e4a2fab7642ada04a5b8453cfd4b1cd' 
  AND token = 'ht1rRR8wnyKZ21gxjzcHWxr2HdIb5d5KkLDNRJcWu8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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