SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c9b53702714c16e276bb3eea594a99835202f963ecd1a86c9cd07bdbea8656d3' 
  AND token = '5q/ScZeps+JGjMpU8onsZhYEXdUQFl8maczYyMg7yYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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