SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c5cbe1560c0f8663c8ef22235176d2c59df3b90a77d40365dff1328595eac79' 
  AND token = 'owDsAOck+yUuyXL/IIDZffbqhjwdtp5FKd3Gjbmcs58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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