SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20fd1db8f96e5adf5b584d36eefd39d982d38eda9efb836e9f26a26982159052' 
  AND token = '+vP0j6XAE9VYBWNqyvI3C8bjAIylUZTaIuG/7vnS4NM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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