SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '208d6a25b4fad536edc55ac0f68099b3f6125f929438c12bfdd84cbe44039bae' 
  AND token = 'k4XxFfSRU1tCS0v0kKu1OSEsXl56rWNvAMutuFXcFGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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