SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a18c046d01bfa38092243e05ab2f7131b8b0f7bc91ab05bdf9b05e757ea2a779' 
  AND token = 'CNmU/TxwYqKwhozgPNaVbYfxGC8A1GJkszRlbAI6xTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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