SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b76deeb3a5cb2e7a77317bea8764b098982ee314190beeae37895e4a04a96921' 
  AND token = 'qIcBvzU2uOOXlDueV2f8hE2RM+Bxv47ILxha4POwftI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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