SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52fc89c880c89e5ec98b48c67994de765f174f6eec5d387d4d8b368b3b68ff2c' 
  AND token = 'kElwk4WesTfSKfPQ2b8LW3wqsfeqbCHQOPcQy0WaN1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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