SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e9319953f5a303f6775df41def7d726e46d3da5c76476144771b4ae701c9fed' 
  AND token = 'DD1z10vOmLfy0vkzWni91DlQlXiN0xB7A1MSUhtLMoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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