SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1c3cd0953f070e45f3d2d19dc45d9647ed955917fa679c04ea310b868b77f988' 
  AND token = 'cS5hV4p9ajMsNSWmeehmG+gKw/Yu+hh4a6EsxHMJ06o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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