SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c941aed6933dbbe18c1f14185385354d267b1caf4f96156bd9ca3f4be0a22567' 
  AND token = 'yjrUmChPWVeRsjzj3bwYMO8+n3dPbOZBM7LFL9hHV5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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