SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7ff6b83c90e02d51ad32058b47884f826e1edfc2fb180ef25da2d03629564738' 
  AND token = 'z3IRIycCyE0RNwNKj5xxiuvluXTmXGuh2oVAoWnGeWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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