SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfcac8d565f39863772fe8231ae86ab3bc0e109273bc4fe6849b44c503a39ee8' 
  AND token = 'Ki5qtOwizcFmt1zBftmIky4SYVHEbv+SgGNEQDhxN1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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