SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ad94c8ed8ecc646df174db9af7dd9bbd57b75e251fb609fd2f5a8dd5400bf18' 
  AND token = 'L5+Q7ca7fXb0kzwTpIC0X1IF/CpkttoJVWRsvKqfN5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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