SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5468b419ef2eee1fc8812ec77f2d5524067c6626fde287e3cbb2a728b3361b44' 
  AND token = 'n71NJ/fJOB3X7Y1vDEGudsp9GzQ3qdlF7IHUA+ah4xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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