SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b692fc7cbfd9b54ad85745d862d7822f62816f458238e18579726687a1f05377' 
  AND token = 'hSThBl37CV8xW00ZnjDfbvrjIsZZgfvvI9bHJbtnOOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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