SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4c3f7a7e1a4b4c4aabafc3844d9d53b7bd6dfa0fe89f6fa0a698be999a471c2' 
  AND token = 'bOSqPQw/WfazgtEGF5Zjyz7cOv0h2p2wVSGP+Uy91k4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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