SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf126b146c4c5428b747fce91c76cb006ae1376bbb16abdd7cb5569e7db4ede3' 
  AND token = '7rwpYUdYScbC66BJdaa5m0XCicvKiqW0NMenAEBiFoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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