SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f471baa30970c2b927e929791e0130eb9ecd5141c5646cecb36316c027c7c2a' 
  AND token = 'pVkcxn7myMt+vaFrJ/Fq7ABAL8b3yrdlWtCmpqlJrcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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