SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1beab2e46083076e5b70409e7affe91b88c2928f74a54de18f5eec31da379126' 
  AND token = 'mtlvlCRSdg1zeBPEy0alzytS7TCRk3sbPqrdV6Q8+rI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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