SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c185dd75094ddc81c1b962b29b309a7af0f046898233094ea29ecf87c656167d' 
  AND token = 'QSr4ZOES+fpegqAnjFPgjPQ+XQ24/HKiP4yDx+FOf3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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