SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb5963831ca20ab644e9a51399c70585a0fb6c9eb6759648d0e30a27add83ded' 
  AND token = '++S48B+BHwIhAx7CUzJmm6Y53UL62rFNZMFQAQKvF38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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