SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d14de0b8f696596d1a52f8cbcf6ae83809f50d485fe37773eedf64739f4a246' 
  AND token = 'KqNmw74z+Q+wf/TqVIpRCXg0MSL7M1i1a9MVrjgEQWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}