SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9480937aecbee4c9d4f66187a6f39742c388cfdd9804aeb8a33e3ca7ef2866e' 
  AND token = 'UoaSlV7PtjTJccDuvvAvR3kkjBw1yhcWKb0bUKRvnno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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