SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e84c21ea0586825b7d939059c099d32bba9ffca017bce8dcfe82796c5798ea18' 
  AND token = 'B6lTYHZ2E9Oxv5oc8XY4/RYRN8WEVUy3rW+9m5lfuOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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