SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a78ea7e999735ba34da031e5ee7068f9a6405d728b5b0eb4e47c40c35e07c232' 
  AND token = 'VT6bRT4qzi/WKxb1bpcSX2kRtucBhsUEz5xTR6xKpRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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