SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '712ebbf7ff0a37ce54647cac5269ecdd8ec4b487a5a74deee1ff57f36c694cb4' 
  AND token = 'IYEZdQhz4wj3SFNJgIRfAsDcs3EgOTLZwGUQsEgL9Do=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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