SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a74e90a5d362db20dd7afab1a6ed4ca3157df7c68b06ff8ef873ae4b1868cb2' 
  AND token = 'JNjqMlpnhfosVuRnC4onY2xrvmoFDxje4XEZlrQkU+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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